This specification relates to systems receiving sequential queries during a single user session and determining query refinements based on the sequence of queries.
The Internet provides access to a wide variety of resources, for example, video files, image files, audio files, or Web pages, including content for particular subjects, book articles, or news articles. A search system can select one or more resources in response to receiving a search query. A search query is data that a user submits to a search engine to satisfy the user's informational needs. The search queries are usually in the form of text, e.g., one or more query terms, and may also include transcriptions of spoken search queries. The search system selects and scores resources based on their relevance to the search query and on their importance relative to other resources to provide search results. The search results are typically ordered according to the scores and presented according to this order.